This invention relates to novel anthelmintic compositions comprising a member of the class of 1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]isoquinolines and having a wide spectrum of effectiveness against cestodes and trematodes.
In the literature and in practice, several compounds are known which are effective against one or more tapeworm (cestode) types, for example, niclosamide [N-(2-chloro-4-nitrophenyl)-5-chlorosalicylamide], quinacrine [2-methoxy-6-chloro-9-[(1-methyl-4-diethylaminobutyl)-amino]-acridine], dichlorophene (2,2'-dihydroxy-5,5'-dichlorodiphenylmethane), etc.
These agents, however, are in part ineffective against the larval forms of the cestodes, as well as against those adult tapeworms which are not located in the intestinal lumen. Also, the echinococci (e.g. Echinococcus granulosus) have been difficult to combat heretofore and the results have not always been certain. Additionally, with several of these agents, e.g., quinacrine and dichlorophene, considerable undesired side effects (e.g. vomiting, nausea) can be expected.
It is possible to utilize other compounds for the combating of schistosomes, for example antimony-containing agents, e.g., stibophen [sodium antimony bis(pyrocatechol-2,4-disulfonate)], niridazole [1-(5-nitro-2-thiazolyl)-imidazolidin-2-one], lucanthone [1-(2-diethylaminoethylamino)-4-methylthiaxanthone hydrochloride], etc. However, optimum medicinal agents which are effective against the various forms of schistosomiasis, which can be utilized without problems also in mass treatments, have not been available on the market heretofore. Furthermore, no agents are as yet commercially available which are equally effective with respect to the most important types of cestodes and simultaneously with respect to schistosomes.